.\"	$NetBSD: kvm_getlwps.3,v 1.6 2009/03/10 23:49:07 joerg Exp $
.\"
.\"Copyright (c) 2002 The NetBSD Foundation, Inc.
.\"All rights reserved.
.\"
.\"This code is derived from software contributed to The NetBSD Foundation
.\"by Nathan J. Williams.
.\"
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.\"modification, are permitted provided that the following conditions
.\"are met:
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.\"   notice, this list of conditions and the following disclaimer.
.\"2. Redistributions in binary form must reproduce the above copyright
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.\"THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\"``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\"TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\"PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\"CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.Dd February 10, 2004
.Dt KVM_GETLWPS 3
.Os
.Sh NAME
.Nm kvm_getlwps
.Nd access state of LWPs belonging to a user process
.Sh LIBRARY
.Lb libkvm
.Sh SYNOPSIS
.In kvm.h
.In sys/param.h
.In sys/sysctl.h
.\" .Fa kvm_t *kd
.Ft struct kinfo_lwp *
.Fn kvm_getlwps "kvm_t *kd" "int pid" "u_long procaddr" "int *elemsize" "int *cnt"
.Sh DESCRIPTION
.Fn kvm_getlwps
returns the set of LWPs belonging to the process specified by
.Fa pid
or
.Fa procaddr
in the kernel indicated by
.Fa kd .
The number of LWPs found is returned in the reference parameter
.Fa cnt .
The LWPs are returned as a contiguous array of
.Sy kinfo_lwp
structures.
This memory is locally allocated, and subsequent calls to
.Fn kvm_getlwps
and
.Fn kvm_close
will overwrite this storage.
.Pp
Only the first
.Fa elemsize
bytes of each array entry are returned.
If the size of the
.Sy kinfo_lwp
structure increases in size in a future release of
.Nx
the kernel will only return the requested amount of data for
each array entry and programs that use
.Fn kvm_getlwps
will continue to function without the need for recompilation.
.Pp
If called against an active kernel, the
.Fn kvm_getlwps
function will use the
.Xr sysctl 3
interface and return information about the process identified by
.Fa pid ;
otherwise the kernel memory device file or swap device will be
accessed and the process is identified by the location passed in
.Fa paddr .
.Sh RETURN VALUES
.Fn kvm_getlwps
returns
.Dv NULL
on failure.
.Sh SEE ALSO
.Xr kvm 3 ,
.Xr kvm_close 3 ,
.Xr kvm_geterr 3 ,
.Xr kvm_getproc2 3 ,
.Xr kvm_getprocs 3 ,
.Xr kvm_nlist 3 ,
.Xr kvm_open 3 ,
.Xr kvm_openfiles 3 ,
.Xr kvm_read 3 ,
.Xr kvm_write 3
.Sh BUGS
These routines do not belong in the kvm interface.
